1. Field of the Invention
The present invention relates to an image pickup apparatus, for example, a digital camera or the like having a blurring compensation function.
2. Description of the Related Art
Conventionally, a digital image pickup apparatus is known as an image pickup apparatus having a blurring compensation mechanism. In an image pickup apparatus described in JP2004-274242A, a fixed cylinder is fitted on a main body case. The fixed cylinder stores a lens barrel on a photographing optical axis. A guide stage is disposed in a side of one end of the fixed cylinder. The photographing optical axis is set as a Z axis direction. A movable frame is held movably along an X-Y plane orthogonal to the photographing optical axis. An image pickup device, for example, a CCD is fixed in the movable frame. The guide stage is fixed on the photographing optical axis within the main body case. The movable frame is guided by the guide stage and driven along the X-Y plane by way of the magnetic force generated by permanent magnets or electromagnetic coils facing the permanent magnets. In the conventional image pickup apparatus, a calculation processing device disposed in the main body case performs a control that moves the CCD fixed in the movable frame following the movement of a photogenic subject image due to blurring by shifting the current applied to the electromagnetic coils in correspondence to tilts of the main body case in the X direction and the Y direction.
JP2004-274242A discloses the mechanism to perform the aforementioned blurring compensation.
In addition, an optical device described in JP2000-66258A includes a shake detection device that detects information of shakes generated in the optical device, a signal processing device that processes output signals of the blurring detection device, a blurring compensation lens driven to compensate blurring of an image generated due to shakes of the optical device and a control device that drives the blurring compensation lens to compensate blurring of the image. Then in order to reduce the influences of the frictional force present when the blurring compensation lens is driven, the control device adds or subtracts a predetermined value to the output value of drive signal corresponding to driven directions of the blurring compensation lens and performs drive control of the blurring compensation lens based on the added value or the subtracted value so that effects of blurring compensation are improved. However, generally, between a static frictional force and kinetic frictional force, the static frictional force is comparatively large. Therefore, when simply a constant predetermined value is added or subtracted to the output value of drive signal of the blurring compensation lens, it is problematic that the drive force becomes insufficient when the blurring compensation lens is driven from a stopped state or the drive force becomes excessive after the blurring compensation lens is driven.